Somewhere along the way, Derek’s pack keeps dying, one by one, and he loses the control he’s never really had. Stiles, turned true alpha in part thanks to his human pack - Scott, recently acquainted with magic, Lydia, genius and a specialist on all things supernatural and Allison, your friendly neighborhood werewolf hunter - knows that once the pack of Alphas is done with Derek’s pack, they will come after his and he won’t be able to protect them how he should.
Derek is not a fan of Stiles and his band of merry misfits, who keep appearing and helping him, saving him and the rest of his pack multiple times. The night Isaac and Cora almost die, Derek tries to tell Stiles that they can do without the help of humans and a boy turned werewolf (and then alpha) by accident.
People fall out of the world sometimes, but they always leave traces. Little things we can’t quite account for. Faces in photographs, luggage, half-eaten meals. Rings. Nothing is ever forgotten, not completely. And if something can be remembered,it can come back.